Spectrometer is an instrument that adopts the principles of optics to resolve complex lights into spectra, and has been utilized mainly in measurement of sample adsorption, transmissivity and reflectivity. Analysis by a spectrometer is nondestructive, chemical characterization capable, wavelength adjustable, highly sensitive and fast. Consequently, spectral analysis has been extensively applied in metallurgy, geology, petrochemical engineering, medicine and healthcare, and environmental protection, as well as in military reconnaissance, space exploration, and resource and hydrological explorations.
In recent years, miniaturization of spectrometers has been realized. For example, Taiwanese Patent No. M370071 discloses a microspectrometer 90, as shown in FIG. 1. The microspectrometer 90 includes a space 91 for disposing a pair of reflective sheets as the waveguide sheets. The gap between the pair of waveguide sheets provides a channel for light passage. The microspectrometer 90 also includes a plurality of spectral components, such as an incident slit device 92, a micrograting 93 and a linear detector 94. In a spectral measurement, a beam of light would enter the microspectrometer 90 from the incident slit device 92, pass through the gap between the waveguide sheets, and project onto the micrograting 93 for dispersing into a plurality of spectral rays of different wavelengths, which are then projected onto the linear detector 94. Thereafter, the linear detector 94 would convert the received spectral rays into electric currents, which are finally analyzed by external components to obtain signals corresponding to the intensities of the spectral rays.
In the microspectrometer 90, positioning of each of the spectral components is required during assembly so as to ensure precision of the resulting microspectrometer. However, existing microspectrometers do not have reference points for component positioning; rather, the spectral components merely abut against certain points on the mechanically shaped housing of the microspectrometer. Such abutting points are formed by line cutting and are insufficient for precise positioning, therefore affecting the precision of the resulting microspectrometer.
More specifically, the abutting points in the existing microspectrometer are formed by line cutting of aluminum sheets, in which deckle edges or uneven cutlines may result from electric spark erosion during the process, and are thus incapable of precise positioning of spectral components. Additionally, composite errors accumulate during line cutting, polishing and other machining as the precision of such processes is approximately 20-30 μm. Therefore, slit member, grating and other spectral components tend to be dislocated during assembly, significantly reducing the accuracy of light projection and precision of light reception and affecting the precision of light signals measured and analyzed by the microspectrometer.
Further, line cutting of waveguide sheets in the existing microspectrometer requires cooling and the use of cutting fluid, which may contaminate the surfaces of the waveguide sheets and cause additional cleaning processes and production costs, and is therefore economically unfavorable. Moreover, polishing following the line cutting also affects the precision of components assembly as it tends to cause lead angles on the waveguide sheets, which impact the projection, transmission and processing of lights of the microspectrometer. Consequently, solving the loss in precision during fabrication and assembly of waveguide sheets and other spectral components has been a key focus in the field.